415 N. Maple Grove Boise, ID 83704
www.PreciseMRM.com
3710024B
Support: (888) 254-1634
Copyright 2009
Sales: (888) 449-0357
p. 8 of 16
Electrical Connections
The IX modules are designed to operate from a continuous voltage source and a
switched voltage source (ignition signal). To track and report total operating hours, as
well as allow the unit to manage its own shut-down sequence, you must connect the
green ignition wires properly. One of the green ignition wires should be connected to a
line on the vehicle that supplies between 7 and 32 volts during operation only. This
could be a signal from the engine hour-meter, an input from the ignition key-switch, or a
similar connection. If the green ignition wire is connected to the alternator for the
switched power source, you will need to confirm that the voltage remains at a minimum
of 7 volts even when the battery is fully charged in order to avoid the following: false
ignition off signals, increased data usage due to more frequent ignition off reports, and
skewed ignition times. The other green wire should be connected to ground. On
equipment with a master disconnect switch, the green wire should be connected to
chassis ground, not battery negative. It does not matter which green wire is connected
to the ignition signal and which one is connected to ground.
When determining where you should make your connections, you should use a volt-
ohm meter or digital multimeter to verify proper voltage levels and determine whether
the voltage is constant or switched, as required by the connection. (NOTE: If the
vehicle is equipped with a master disconnect switch for the battery this does not qualify
as a “switched” power source. An example of a proper switched power source would be
something that only comes on when the ignition has been turned on, such as an engine
hour-meter).
The threaded antenna connectors on the IX modules should only be connected finger
tight. Do not use a wrench or pliers to make these connections or damage may occur.
Figure 2 shows all of the connections available.
The ends of the wires of the supplied power harness are terminated with butt-splice
connectors designed for 18-22 AWG wire. Strip approximately ¼” (7mm) of insulation
from the wire that will connect to the harness and be sure to use the proper crimping
tool. A slight tug on the wire after crimping is recommended to ensure a firm
connection.
The input connections are usually wired with one of the wires connected to the point you
want to measure and the other wire connected to either ground or power, depending on
the state of the signal when the switch is on. If the signal measures low voltage (<
0.8V) when the switch is on, the second wire should be connected to power. If the
signal measures high voltage (> 5V) when the switch is on, the second wire should be
connected to ground. Figure 3 shows examples of input connections.
